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The City of Portland, Oregon

Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Ave, Suite 613, Portland, OR 97204

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Dentistry: Guide to New Dental Amalgam Rule


For questions or more information, please email DentalAmalgam@


Initial Compliance Certification

Equipment & Amalgam Waste Management Log

Annual Certification


By Email
Send compliance forms by email to DentalAmalgam@

By Mail
City of Portland
Bureau of Environmental Services
Water Pollution Control Lab
Attn: Dental Amalgam
6543 N Burlington Avenue
Portland, OR 97203-5452

Nationwide, the Environmental Protection Agency (EPA) estimates that 50 percent of mercury entering publicly-owned wastewater treatment facilities comes from amalgam discharged by dental practices. To reduce this toxic metal in treatment facilities, the EPA established federal requirements for dental practices to properly manage amalgam waste. These requirements are established in chapter 40 of the Code of Federal Regulations part 441 (commonly called the Dental Amalgam Rule).


Dental amalgam, a common filling material, is made mostly of mercury and a mixture of other heavy metals: silver, tin, copper, and zinc. When introduced into the environment, mercury from amalgam has a toxic effect on aquatic organisms. Portland's wastewater treatment facility is not designed to remove mercury, so any mercury discharged from dental practices has the potential to enter the Willamette and Columbia rivers. Controlling amalgam discharges from dental practices benefits the health of our rivers.

The City’s Role

The EPA requires the City to implement the rule for dental practices that discharge wastewater to a Portland-owned wastewater treatment facility.

Dental practices that report to the City of Portland:

  • Are directly connected to the City’s sanitary sewer system.
  • Are connected to a surrounding city or district that sends a portion of their sewer to a Portland treatment facility. These include Clackamas, Gresham, Dunthrope-Riverdale, Lake Oswego, Milwaukie, Tualatin, Hillsboro, and West Hills Service District. If you receive a notice from Portland, your practice has been identified by a sewer mapping database as a discharger to the City of Portland.

Dental Practices that do not report to the City of Portland:

  • Send wastewater to another city or district’s treatment facility.
  • Are connected to a septic tank, cesspool, or holding tank.

Dental practice required Best Management Practices (BMP)

  • Install, operate, and maintain an approved amalgam separator.
  • Inspect the amalgam separator(s), at a minimum, once per month to ensure proper operation and confirm that there is no bypass of the separator.
  • Repair or replace defective amalgam removal equipment/components in accordance with the manufacturer’s specifications.
  • Maintain the amalgam separator(s) regularly by replacing retaining cartridges, separator canisters, filters, and/or other treatment units annually, or whenever the unit reaches the manufacturer’s design capacity, whichever comes first.
  • Do not use oxidizing or acidic cleaners to flush dental unit water lines.
  • Collect scrap amalgam from chair-side traps, screens, vacuum pump filters, dental tools, and/or other collection devices for off-site disposal. Scrap amalgam must not be flushed down the drain.
  • Maintain logs documenting amalgam separator maintenance activities and waste amalgam disposal.

Required BMP Applicability

Dental practices required to implement BMPs

  • All dental practices that place or remove amalgam on a regular basis, such as offices, large dental institutions, schools, and clinics.

Dental practices exempt from BMPs

  • Dental specialty practices like oral pathology, oral and maxillofacial radiology or surgery, orthodontics, periodontics, or prosthodontics.
  • Mobile units.
  • Dental practices that do not place or remove amalgam except in limited, emergency, unplanned, or unanticipated circumstances.

Reporting Requirements

Initial Certification Report – Required to be completed and submitted by all Dental Practices, including those that are exempt from the BMPs.

Initial Report Due Dates

  • If your practice opened after July 15, 2017 the report is due 30 days after the practice opened.
  • If you purchased an existing practice, the new owner must submit the report within 30 days of taking ownership.
  • Practices that were in existence prior to July 15, 2017 are being contacted by the City and given a due date for the report. Practices are welcome to download the report and submit it to the City prior to an established due date.

The EPA requires an original signature on the initial report. Please mail the original form to:

City of Portland Bureau of Environmental Services
Water Pollution Control Lab
Attn: Dental Amalgam Program
Portland Water Pollution Control Lab
6543 N Burlington Ave.
Portland, OR 97203

Annual Certification Report – Only Dental Practices that are required to implement the BMPs must submit the annual certification report. Exempt practices do not need to meet this ongoing reporting requirement.

This report must be received by the City no later than January 15 of each year starting in 2021.  The report does not require an original signature and can be sent to the address above or via e-mail to:

What to Expect After Submitting the Initial Certification

Applicable dental practices will be issued a discharge authorization from the City. The authorization documents the required BMPs. The City will periodically conduct inspections of dental practices to ensure BMPs are in place and being followed. In addition to a physical inspection of amalgam capturing devices, the following records will be reviewed:

Dental practices that claim the exemption on the initial certification report will receive a letter acknowledging their exemption status.  No further actions are required for these facilities, unless the practice changes and it becomes covered by the Dental Amalgam Rule.

Program Fees

The cost for the City to administer this program will be recovered with an annual fee. The City will send invoices to applicable dental practices.

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